In all cases, however, the concept behind dry-cargo merchant ship design has altered dramatically in the period since World War II. Nowadays, vessels must be ‘cargo-friendly‘ basically designed and equipped to speed cargo handling at load and discharge ports within a minimum of time and with a minimum of shore labour but with the capability of efficiently carrying the maximum amount of freight earning cargo. The soaring cost of oil fuel (referred to as ‘bunkers‘) since the 1970’s has also meant that modern main engines have been designed to consume considerably less during sea passages than was once the case, and this emphasis on ‘performance‘ has led to hull design innovations, such as the wide-spread introduction of the ‘bulbous bow‘. Developments are still taking place in both engine and hull design, although now the driving force is preventing airborne pollution. Ships are obliged under international conventions to minimise their polluting effect and some states – or in the case of the European Union, groups of states – have expressed their intention of imposing stricter limits still. Reducing pollution from engines can mean a small increase in fuel consumption depending on the technology chosen but experts and ship designers share a belief that changes to hull designs could result in a 10 to 20 per cent cut in fuel consumption within the next ten to fifteen years. Some of the changes proposed (multi hulls and longer narrower vessels) may not meet with operator approval and may also need changes to ways ships are measured for tonnage and charging purposes.